Crystal structure of 2-cyano-N′-(cyclohexylidene)acetohydrazide

In the title compound, C9H13N3O, the cyclohexylidene ring adopts a chair conformation and the bond-angle sum at the C atom linked to the N atom is 359.6°. The cyanoacetohydrazide grouping is close to planar (r.m.s. deviation for the non-H atoms = 0.031 Å) and subtends a dihedral angle of 64.08 (4)° with the four C atoms forming the seat of the chair. The C=O and N—H groups are in a syn conformation (O—C—N—H = −5°). In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops; this dimer linkage is reinforced by a pair of C—H⋯O interactions, which generate R 2 2(14) loops. The dimers are linked by C—H⋯Nc (c = cyanide) interactions into [100] ladders, which feature C(4) chains and R 4 4(20) loops.

In the title compound, C 9 H 13 N 3 O, the cyclohexylidene ring adopts a chair conformation and the bond-angle sum at the C atom linked to the N atom is 359.6 . The cyanoacetohydrazide grouping is close to planar (r.m.s. deviation for the non-H atoms = 0.031 Å ) and subtends a dihedral angle of 64.08 (4) with the four C atoms forming the seat of the chair. The C O and N-H groups are in a syn conformation (O-C-N-H = À5 ). In the crystal, inversion dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds generate R 2 2 (8) loops; this dimer linkage is reinforced by a pair of C-HÁ Á ÁO interactions, which generate R 2 2 (14) loops. The dimers are linked by C-HÁ Á ÁN c (c = cyanide) interactions into [100] ladders, which feature C(4) chains and R 4 4 (20) loops.  Table 1 Hydrogen-bond geometry (Å , ). Data collection: CrystalClear (Rigaku, 2012); cell refinement: Crys-talClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97.

S1. Experimental
Cyclohexanone (0.98 g, 0.01 mol) was added to a solution of cyanoacetylhydrazine (0.99 g, 0.01 mol) in 1,4-dioxane (20 ml). The mixture was heated under reflux for 2 h and then poured into a beaker containing an ice/water mixture: the solid product was collected by filtration. Yellow slabs of the title compound were obtained by slow evaporation of an ethanol solution.

S2. Refinement
The N-bound H atom was located in a difference map and its position was freely refined. The C-bound H atoms were placed in idealized locations (C-H = 0.99 Å) and refined as riding atoms. The constraint U iso (H) = 1.2U eq (carrier) was applied in all cases.

Figure 1
The molecular structure of the title compound showing 50% displacement ellipsoids.

Figure 2
An inversion dimer in the crystal of the title compound, with N-H···O and C-H···O hydrogen bonds indicated by double-dashed lines. Symmetry code: (i) -x, 1-y, -z.

Figure 3
Part of a [100] double chain in the crystal of the title compound, with hydrogen bonds indicated by double-dashed lines.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.